Want to be able to butt first entry but don't know what size? Slide your chair back from your computer desk until you can put your feet on the edge of the desk. Measure the distance between the top of the chair back -level with the desk edge and the desk edge. That should give you an idea of length.

Maybe I'm just daydreaming, but how about a hinged deck in front of the coaming that'll swing left or right and lock in place. The outboard end would have an float. This way you could always flip a latch, swing the hatch open (bonk yourself on the head) and voila you'd have a self bracing kayak that you could get back into even if your leg was in a splint. Nah wouldn't work-leak too much....